Alberta Infant Motor Scale (AIMS)

Original Editor - Padraig O Beaglaoich

Top Contributors - Padraig O Beaglaoich, Naomi O'Reilly, Robin Tacchetti and Jess Bell  

Objective

The Alberta Infant Motor Scale (AIMS) is a standardised observational examination tool used to assess the maturation of gross motor skills of infants from term (i.e. 40 weeks gestation) to 18 months post-term. The AIMS was developed as a reference guide for the development of infants based on the age related norms of 2200 infants in Alberta, Canada.

It can be used as a screening tool to detect and track early developmental delays. It compares a child's level of motor development against the expected norms for their age in four categories: prone, supine, sitting and standing.

Intended Population

Figure.1 Infant Crawling

The AIMS can be used with all infants aged under 18 months to identify delays or changes in motor skill development. It may be used for infants who:

• show typical development with no medical concerns
• do not have specific factors in their history, but motor development delays are suspected
• are at higher risk of developmental delay due to genetic, prenatal, perinatal, neonatal, postnatal, or environmental complications
• have been given a specific diagnosis that affects motor skill development (e.g., Down syndrome, bronchopulmonary dysplasia)

The AIMS should NOT be used for infants who use altered movement patterns to compensate for functional limitations (e.g., paralysis, spina bifida, hypotonia, muscle spasticity) as their unique motor development improvements may not be reflected in the AIMS.

Tool Description

Figure.2 Infant Prone Push Up

The AIMS is a 58-item observational scoring tool. These items are divided into four position-centric sub-scales:

1. Prone (21 items)
2. Supine (9 items)
3. Sitting (12 items)
4. Standing (16 items)

Equipment Required

• AIMS Manual
• AIMS Score Sheet and Graph
• Examining table or other raised surface for younger infants
• Firm mat or carpet for older infants
• Low bench or chair for some items on the scale
• Toys appropriate for infants younger than 18 months

Set-up

The AIMS can be conducted in the home or clinic. The assessment for younger infants can be performed on an examining table or raised surface. For older infants, the assessment should be conducted on a firm mat or carpeted area of the floor.

Method of Use

It is important that the assessor familiarise themselves with the administration and scoring guidelines of the AIMS prior to the assessment. The assessment takes a maximum of 20-30 minutes to complete. The assessor observes the motor patterns of the infant and compares them to the scale sheet.

Scoring

Figure 3: Alberta Infant Motor Scale (AIMS) Centile Ranks Graph.

The assessor will preferably complete the scoring after the assessment has finished.

The scoring sheet consists of a photo and a short description of the movement being assessed. The movements begin with the most basic presentations of prone lying, supine lying, sitting, and standing and progress incrementally to more advanced movements.

During the assessment, the evaluator observes the movements of the child and scores each movement component as either “observed” or “not observed”. There is no option to score the patient on ‘emerging’ movement patterns. The patient should not be accredited for items reported by parents / caregivers.

The least advanced and most advanced movements observed in a given position (prone, supine, sitting, standing) create the ‘motor window’ for the patient in that position. All movements within the motor window for each position must be recorded as "observed" (O) or "not observed" (NO).

The assessor scores the patient one point for each movement that is “observed” within each motor window. The accumulative score of all four positions provides the 'total score'. The total score is recorded against the corrected gestational age of the patient on a graph of normative data for infant motor function. The graph in Figure 3 contains the percentile (5^th, 10^th, 25^th, 50^th, 75^th, 90^th) norms of infant motor function. The assessor determines at which percentile of motor development the patient is for their age based on the graphed normative values and records it on the scoring sheet.

Evidence

Standardisation

The data used to develop the AIMS was based on the assessments of 2202 infants aged less than 18 months who were living in Alberta, Canada between 1990 and 1992. The normative values from this group were expressed as the mean, standard deviation, and percentile rank for the total score for each month of age, and time norms for the achievement of each item. These reference figures and norms with percentile ranks are accessible in the AIMS Manual.

The interrater and test-retest reliability of the original scale and was found to be 0.99. The concurrent validity of the original scale was assessed against the Bayley Scales of Infant and Toddler Development (BSID) and the Peabody Development Motor Scales (PDSM). Concurrent validity with the BSID was 0.98, and 0.97 with the PDSM.

Re-evaluation of the scale was performed in 2014. Developmental norms were assessed in 650 infants from Alberta over a two year period. Darrah et al. reported a correlation coefficient of 0.99 between the original and re-evaluation groups, and concluded that the validity of the initial research was unchanged.

Normative development of infants in other countries have been assessed using the AIMS. Results from these studies have formed population-specific normative values for several of these countries, such as Netherlands, Brazil, Serbia, Korea, Greece, Poland, Spain, Thailand, and Taiwan.